British Rail Class 306
Class 306 at Liverpool Street in 1975
In service	1949–1981
Manufacturer	Metro Cammell and BRCW
Order no.	363: 65201–65292 364: 65401–65492 365: 65601–65692[1]
Constructed	1949[2]
Refurbished	Rebuilt 1959–1961[3]
Number built	92 trainsets
Number scrapped	91
Formation	3 cars per trainset. As built: DMBSO+TSO+DTSO[4] As rebuilt: DMSO+TBSO+DTSO[2]
Diagram	BR TOPS codes rebuilt units EA203 DMSO EE211 DTSO EJ201 [5]
Design code	AM6
Fleet numbers	306001–306092 (sets) 65201–65292 (DMBSO later DMSO) 65401–65492 (TSO later TBSO) 65601–65692 (DTSO)[6]
Capacity	48S (DMBS0) rebuilt 62S (DMSO) 68S (TSO) rebuilt 46S (TBSO) 60S (DTSO)[2]
Operators	British Rail
Depots	Ilford[2]
Lines served	Liverpool Street–Shenfield, Great Eastern Suburban[7]
Specifications
Car body construction	Steel[5]
Train length	177 ft 7 in (54.13 m)[3]
Car length	60 ft 4+1⁄4 in (18.396 m) (DMSO)[4] 55 ft 0+1⁄2 in (16.777 m) (TBSO)[4] 55 ft 4+1⁄4 in (16.872 m) (DTSO)[8]
Width	9 ft 3 in (2.82 m)[4]
Height	13 ft 1 in (3.99 m)[3]
Doors	Bi-parting sliding[3]
Articulated sections	3
Maximum speed	75 mph (121 km/h)[3]
Weight	105 long tons (107 t; 118 short tons) (total) 51.7 t (50.9 long tons; 57.0 short tons) (DMSO) 26.4 t (26.0 long tons; 29.1 short tons) (TBSO) 27.9 t (27.5 long tons; 30.8 short tons) (DTSO)[2]
Traction motors	4 × Crompton Parkinson[4]
Power output	4 × 157 hp (117 kW)[4]
Electric system(s)	1500 V DC Overhead line (original) 6.25 kV and 25 kV 50 Hz AC Overhead line (rebuilt)
Current collector(s)	Pantograph
UIC classification	Bo′Bo′+2′2′+2′2′
Bogies	Thompson[9] / LNER ED6 / ET6[5]
Braking system(s)	Air (EP/Auto)[3]
Safety system(s)	AWS
Coupling system	Screw[2]
Multiple working	Within class
Track gauge	4 ft 8+1⁄2 in (1,435 mm)

The British Rail Class 306 was a fleet of electric multiple unit (EMU) trains introduced in 1949. It consisted of 92 three-car trains which were used on the Great Eastern Main Line between Shenfield and London Liverpool Street.

Class 306 trains were built to a pre-Second World War design by Birmingham Railway Carriage and Wagon Company (Driving Trailer) and Metro Cammell (Driving Motor Brake and Trailer) and were equipped with Metrovick traction equipment Crompton Parkinson traction motors. Each carriage featured two sets of twin pneumatic sliding passenger doors, which could be opened by either the guard or the passengers, who could use buttons fitted inside and outside the doors. The order was placed by the LNER in 1938, but official delivery did not commence until February 1949.^[10]

When built the trains were energised at 1,500 V direct current (DC) which was collected from overhead wires by a diamond pantograph located above the cab on the Motor Brake Second Open (MBSO) vehicle.

From 1959 to 1961 the overhead wires were re-energised at 25 kV alternating current (AC) (and 6.25 kV AC in the inner London areas where headroom for the overhead wires was reduced) and the trains were rebuilt to use this different electrical system. A transformer and rectifier unit was fitted to the underframe between the bogies of the intermediate Trailer Brake Second (TBS) and the pantograph, now a more modern Stone Faiveley AMBR design, was moved to the roof of this carriage. Because this reduced the headroom inside the train, the guard's compartment was relocated to be directly below the pantograph. The trains were then numbered 001–092 with the last two digits of each carriage number (LNER coaching series numbers used) the same as the unit number.

Units being made up of three coaches, trains were formed up to three units (nine coaches)^[10] although off-peak trains formed of only two units (six coaches) could be seen. This meant that the standard formation could carry 528 seated passengers plus another 696 standing, making 1,224 passengers, compared with about 1,000 passengers in the steam trains that they replaced.^[10]

There is a record of a single three-coach unit hauling a Class 47 and train into Chelmsford after the locomotive failed on a London Liverpool Street-to-Norwich express.^[11]

The 92 units were originally numbered 01 to 92, becoming 001 to 092 upon conversion for AC operation. Coach numbers were:

• DMSO: 65201 to 65292
• TBSO: 65401 to 65492
• DTSO: 65601 to 65692

In all cases the last two digits of the unit number matched those of the coach numbers. The whole fleet was allocated to Ilford depot.

The Class 306 trains were withdrawn in the early 1980s. Unit 306017 was preserved at Ilford depot; it had been repainted in a near-original green livery, albeit with a yellow warning panel on the front to comply with then-current safety regulations. In the early 2000s it was restored to operational condition by First Great Eastern.^[12]

The unit was later in store at MoD Kineton awaiting the resolving of issues such as asbestos contamination. The contamination was removed at Eastleigh Works and the unit was transferred by rail to the East Anglian Railway Museum in June 2011 for display as an exhibit, under a four-year loan agreement from the National Railway Museum. It was moved to Locomotion: the National Railway Museum at Shildon in October 2018 so that it could be assessed before restoration.^[13] It is scheduled to move to York when space becomes available.^[12][14]

• Class 506 EMUs – similar to the Class 306 EMUs, but built for the Manchester–Sheffield–Wath electric railway

• Harris, M. (1973). Gresley's Coaches. Newton Abbot, UK: David & Charles. ISBN 978-0-71535-935-8. OCLC 746436.
• Mallaband, P.; Bowles, L.J. (1974). The Coaching Stock of British Railways, 1974. Kenilworth, UK: Railway Correspondence & Travel Society. OCLC 614206200.
• Fox, P. (1987). British Railways Pocket Book No. 2: Multiple Units (Summer–Autumn 1987 ed.). Sheffield, UK: Platform 5 Publishing. ISBN 978-0-906579-74-9. OCLC 613347580.
• Swain, A. (1990). British Railway Fleet Survey 11: Overhead Line Electric Multiple Units. Ian Allan Publishing. ISBN 978-0-71101-902-7. OCLC 21874638.
• Fox, P. (2002). British Railways Locomotives & Coaching Stock 2002. Sheffield, UK: Platform 5 Publishing. ISBN 978-1-90233-625-1. OCLC 931408403.
• Glover, J. (2003). Eastern Electric. Hersham, UK: Ian Allan Publishing. ISBN 978-0-71102-934-7. OCLC 51738486.
• Longworth, H. (2015). British Railways Electric Multiple Units to 1975. Addlestone, UK: Oxford Publishing Company. ISBN 978-0-86093-668-8. OCLC 923205678.

Wikimedia Commons has media related to British Rail Class 306.

• Johnston, Howard (February–March 1982). "Last of the Shenfield rattlers". Rail Enthusiast. EMAP National Publications. pp. 44–46. ISSN 0262-561X. OCLC 49957965.